Relatively Low Incidence of Secondary Cancers After Use of Revlimid for Treatment of Multiple Myeloma

Posted on June 27th, 2011 by

Three separate studies have suggested that the benefit of Revlimid® (lenalidomide) for the initial treatment of patients with multiple myeloma outweighs the possible increased risk of developing secondary malignancies. These three studies were presented at the 2011 annual meeting of the American Society of Clinical Oncology.

Multiple myeloma is a cancer of plasma cells, which are a special type of white blood cell that are part of the body’s immune system. Patients with multiple myeloma have increased numbers of abnormal plasma cells that may produce increased quantities of dysfunctional antibodies detectable in the blood and/or urine.

Revlimid is an oral medication that can stop or slow the growth of cancerous myeloma cells within the bone marrow. It has been approved by the US Food and Drug in combination with dexamethasone for multiple myeloma patients who have received at least one prior therapy. Revlimid has also been evaluated in combination with other agents for the initial treatment of patients with newly diagnosed myeloma.

All cancer chemotherapy drugs have the potential for causing secondary cancers. Recently, there has been concern that the addition of Revlimid to other chemotherapy could be associated with an unacceptable increased incidence of secondary malignancies. The three studies sought to determine the risk of adding Revlimid to other chemotherapy agents for the treatment of patients with multiple myeloma.

A multi-center international study compared the incidence of second malignancies in patients who were treated with a regimen of Revlimid, melphalan and prednisone with (n=150) or without Revlimid maintenance (n=152) or with melphalan and prednisone without Revlimid (n=153).[1] The incidence of solid tumors appeared to be similar in the three groups but there were two cases of myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) in each of the two Revlimid groups (0.07%) versus none in the melphalan and prednisone group. These authors reported that the addition of Revlimid reduced disease progression by 60% with a median progression-free survival of 31 months for the Revlimid group compared with 13 months for the no-Revlimid group. These authors concluded that “The rate of secondary cancers is low, and the benefit-risk ratio is strongly in favor of continuous Revlimid maintenance.”

A multi-center US study also reported on the long-term outcomes of 72 patients treated with Biaxin® (clarithromycin), Revlimid and dexamethasone.[2] Patients on this study received therapy until progression of disease. The researchers reported that 16% of patients in this study developed secondary malignancies, 6 of which were skin cancers and none of which were blood cancers. This seems like a high incidence but these authors reported that the 2.85% per year frequency seen in this study was similar to the 2.1% per year frequency that would be expected in patients without myeloma. In addition, the most common type of secondary cancer was cancer of the skin which is often highly curable. Furthermore, the Revlimid regimen used in this study was extremely effective with a 38.9% complete remission rate.

The third study presented at ASCO was a US multi-center trial evaluating the risk of secondary cancers in patients receiving Revlimid and dexamethasone (n=353) versus placebo and dexamethasone (n=350) for relapsed multiple myeloma.[3] Treatment in both arms was given until disease progression. There were eight cases of secondary cancer in the Revlimid arm and two cases in the control group. There were two cases of MDS in the Revlimid arm and none in the control arm. The median survival of patients receiving Revlimid was 31 months compared with 24 months for the control group. These authors concluded that “the observed secondary cancer rates in both treatment arms were comparable to rates expected for the general population.”

These three studies will undoubtedly be followed by other studies in attempts to determine the impact of Revlimid on secondary cancers. However, at the present time the anti-myeloma effects of Revlimid appear to outweigh any adverse effects due to secondary cancers.